204 



specimens of the supposed inhaerens were ordered from Woods Hole, 

 the american type-locality of the species. The examination of these 

 beautifully preserved specimens, shows that they are distinctly dif- 

 ferent from the European specimens of inhaerens from the Norwegian 

 coast (The differences are mentioned below in the description of 

 Leptosynapta tenuis (Ayres) pag. 209). I therefore cannot hesitate 

 in supposing that inhaerens (O. F. Müller) is totally wanting at the 

 American coasts, where it is represented by tenuis (Ayres) in the 

 Atlantic Ocean and by clarki Heding in the Pacific Ocean. 



The specimens received from Woods Hole agree pretty well 

 with the description of tenuis (Ayres) and as they are from the 

 same locality I think it quite justifiable to refer them to that species 

 which must be regarded as a valid species, distinctly different 

 from inhaerens. As to the identity of tenuis and girardii (Pourtalès) 

 I am in very great doubt, but the question cannot be answered 

 definitely on base of the material in hand. Beside tenuis and girardii 

 Gl ark has referred Selenka's two species gracilis and albicans 

 to inhaerens. This is, according to what is said above, evidently 

 erroneous; while gracilis without any doubt is but a specimen of 

 tenuis with the calcareous deposits partly dissolved, albicans must 

 be regarded as a valid species from the American coast. 



In the description of albicans (Beiträge zur Anatomie und Sy- 

 stematik der Holothurien, pag. 363) Selenka does not say anything 

 about rods in the skin. This he may perhaps have forgotten; as 

 he has, however, both described and figured the rods from the 

 tentacles, and in the description of other species for instance that 

 of Synapta agassizii Selenka, he has figured the corpuscles from 

 the skin, we may well be right in supposing that albicans (like 

 Leptosynapta lens Heding and Leptosynapta circopatina Clark), is 

 lacking rods in the body-wall. If so, the specimens from Kilizut 

 Harbour, which Clark in the "Puget Sound Echinoderms" has 

 referred to albicans with a ?, cannot be referred to this species. 

 In the collection of Dr. Mortensen, there are from the Pacific 

 coast of North America, four different species of Leptosynapta, but 

 none of them may be referred to albicans. Clark's specimens 

 from Kilizut Harbour are closely related to only one of them, 

 clarki Heding, from which species they differ in lacking sensory 

 cups on the tentacles and rods in the interambulacra. But as Clark 



