360 ECHTNODERMS OF THE BRITISH ISLES 



3. A marginal fringe of appendages around the ventral surface of 



the body. Tentacles large, with broad disk. A tail-like 

 prolongation of the body may be present Psychropotidce 



No marginal fringe ; no tail -like prolongation. Tentacles with 

 small disk, often with finger-like lobes in the margin, or nearly 

 pedicel -shaped ........ 4 



4. Calcareous bodies mainly wheels . . I. Lcetmogonidce 

 Calcareous bodies pointed rods or derivatives from such, or four- 

 armed bodies with 1-4 outer projections from base of arms ; 

 wheels rarely present and then scarce . . . Elpidiidos 



I. Family L.^tmogonid^ 



Body usually rather long, more or less cylindrical. Skin more 

 or less gelatinous, transparent. Dorsal papillae present all along 

 the radii, flexible, their calcareous corpuscles not longitudinally 

 directed spicules. Tube-feet of latero- ventral ambulacra well 

 developed and numerous, mostly lacking in the mid-ventral 

 ambulacrum. Calcareous bodies wheels, which occur in great 

 numbers, and other small bodies. Calcareous ring composed of 

 an imperfect network, not distinctly separated into radials and 

 interradials. Gonads branched. Mesentery in the shape of a 

 continuous membrane, present also along the second intestinal 

 loop. 



Two genera of this family are represented in the British seas, 

 but one more, namely Pannychia Theel, may be expected to be 

 represented there also, the species P. glutinosa Herouard having 

 been found off the Azores, 2102 m. (" Princesse Alice " ; only 

 one specimen known). ^ Possibly also the genus L(Etmoj)hasma 

 Ludwig will be found there, a specimen too badly preserved for 

 identifying with certainty, but probably belonging to this genus, 

 having been found off the Azores, 1385 m. (" Princesse Alice "). 



Key to the genera of Lcetmogonidce known from or likely to 

 occur in the British seas. 



1. Mid-ventral ambulacrum naked ; dorsal papillae in a single or 



double series along each ambulacrum .... 2 



Mid- ventral ambulacrum with a double row of tube -feet or small 



papillae ; dorsal papillae crowded . . . . .3 



2. Papillae of dorsal ambulacra long, not retractile 



I. Lcetmogone Theel 

 Papillae of dorsal ambulacra small, retractile 



II. Benthogone Koehler 



^ Miss Deichmann has informed the author that in her opinion 

 Pannychia glutinosa Her. is only a young Benthodytes lingua Perr. 



