(1) Loxosoma loxalina n.s.--Lophophore larger than the body and bears sixteen tentacles, of which four are longer than the others. These four are on the oral part of the lophophore, which is slightly inflected along that region. The stalk is considerably longer than the calyx, and terminates in a circular foot with radiating supporting cells. There is no foot-gland. The body and the lophophore are beset with deeply placed ectodermal organs along the lateral margins, of which organs there are usually four pairs, giving a some what angular appearance to the calyx. It was found living cominensally with a Maldauid worm (which was not identified) on the Morven shore of the Sound of Mull in Scotland.
(2) Loxosoma saltans n.s.--Lophophore larger than the body and bears sixteen tentacles, of which four are longer than the others and are moved separately, and are always outside and over the others when contracted. They bear stiff hairs on the outer edge of their tips. As in L.loxalina the oral part of the lophophore is indented. The specific name indicates its habit of locomotion by jumping, in which action the four large tentacles take a part. The stalk is shorter, or only slightly longer than the calyx, and terminates in a circular foot as in L. loxalina. There is no foot-gland. The glandular diverticula of the alimentary canal are highly developed. The body has two ectodermal organs, or less, which are pedunculate and attached to the ventro-lateral surface just below the buds. They are larger and placed higher than the corresponding organs of L. Davenporti. The species was found in the tube of a Maldanid worm Clymene ebiensis on the Skye shore of the Kyle of Loch Alsh in Scotland.
(3) The alimentary canal of L. saltansis differentiated more markedly into glandular, absorptive and excretory regions than L. loxalina. Two very distinct proximal diverticula appear to secrete some substauce into the cavity of the gut, probably digestive in action; a more distal pair of diverticula seem to be more of the nature of a liver. The whole alimentary canal is a single layer of cells.
(4) The nervous system consists of the usual pair of ganglia in both species, in L. saltans the main nerves can be traced to lophophore, body-wall, kidneys and gut. Sensory hairs occur on the tentacles. A chain of cells along the stalk may be nervous.
(5) In L. saltans the excretory organs are divided into (i) lophophoral and (ii) body-kidneys, which are large vacuolated cells which perhaps lie in contact with ducts, but the external openings could not be traced. No sign of ciliation of any part of these ducts is apparent in the living L. saltans.
In L. loxalina the excretory organs are on a rather different plan. In L. saltans the (iii) rectum takes an important part in excretion, certain cells accumulating excretory products in vacuoles which presumably burst into the cavity of the rectum.
(6) In L. loxalina the reproductive glands consist of a pair of gonads which may be hermaphrodite, with ducts joining in the median plane where there is a shell-gland, whence a median duct runs to open into the atrium between the epistome and the lophophoral hood. In L. saltans the gonad is single and median, with the duct opening on a papilla between the epistome and lophophoral hood.
(7) In neither species is there any lateral expansion of the body into alæ. The general mesodermal tissue is more abundant iu L. loxalina than in L. saltans.
Memoirs: Loxosoma Loxalina and Loxosoma Saltans--Two New Species
