244 ANNALS OF SCOTTISH NATURAL HISTORY 



an imperfect instrument. The balance of characters seems 

 to show that the two species are practically identical. 



On the other hand, the general characters, and in 

 particular the lip, are extremely like C. labiatus, in which 

 species, however, Mr. Gosse, though he appears to have 

 studied it repeatedly, never detected any protrusible auricles, 

 nor any trace of gelatinous covering. At the same time, if 

 our species were studied in only a small quantity of water, it 

 might be examined over and over again and its auricles never 

 seen. Mr. Gosse figures the lumbar sense-organs as single 

 stout bristles, but he seems to have had some doubt on this 

 point, as in the description he calls them " apparently 

 single. 



Proceeding to the internal structure : — The BRAIN, 

 which is large and transparent, is formed apparently of three 

 lobes as described by Gosse in C. labiatus. Two lobes are 

 lateral, short, and each containing a well-defined rounded 

 spot of dark pigment. The central lobe is long, dependent, 

 enlarged at the extremity, and free from granular or pigment- 

 ary deposit. The red EYE, which is stated by Gosse to be 

 situated in C. labiatus and C. cerberus y on the narrow waist 

 of this central lobe, is here placed more anteriorly, in the 

 very front of the brain. The TROPHI, of which I have not 

 made a special examination, seem to correspond with the 

 figure of C. labiatus. The OESOPHAGUS is very long, narrow, 

 and transparent. The STOMACH is wide and large, but has 

 never shown to me that peculiar appearance of being divided 

 up by constrictions into squares which, according to Gosse, 

 is in C. labiatus " not accidental but characteristic, being 

 seen in every example that has occurred to me, and dis- 

 tinguishing the species from all its congeners." The two 

 ovate GASTRIC GLANDS are present, perched on the anterior 

 border of the stomach. The NEPHRIDIA {branchiae of Gosse), 

 are in the usual form of convoluted tubes, on each side of 

 which I have seen at least four ciliated funnels (" vibratile 

 tags.") In several specimens the ovary appeared as a single 

 row of globular, nucleated, transparent cells. 



