ON JULINIA. 13 



requiring a name, I give the animal at the same time a new 

 specific one in the face of what uncertainty remains as to its 

 identity with Professor Herdman's type. 



As regards the affinities of the new genus, we are confronted 

 by the fact that the diagnoses of recognised families appear to 

 be somewhat artificial, and certainly do not lend themselves 

 very readily to the reception of new forms. Taking, however, 

 the received families as they at present go, Julinia is obviously 

 excluded from the Polyclinidae by the absence of a post- 

 abdomen. This negative character, together with the distinct 

 separation of thorax from abdomen, are characters common to 

 the three families of Distomidse, Didemuidse, and Diplo- 

 somidse. From the last two families our species is excluded 

 by the absence of retractile muscles in the vascular processes, 

 by the large anal languets (absent in Giard's definition from 

 the Diplosomidse), by the want of the calcareous spicules so 

 characteristic of the Didemnidse, and by the characters of 

 the testis and vas deferens, which latter in the Didemnidse 

 is spirally coiled round the single large testis. Narrowing 

 down our genus accordingly to the Distoraida3, we find that 

 it agrees with that family in the numerous spermatic vesicles 

 of the testis, as well as with individual genera of that family in 

 its incubatory pouch and large atrial languet. The incubatory 

 pouch is common to Colella and Distaplia, while the atrial 

 languet is absent in Colella. The general sum of the 

 characters, then, seems to bring our genus nearest to Dis- 

 taplia, with which latter genus it further agrees in the 

 characters of the branchial sac with its four rows of long 

 stigmata crossed by intermediate transverse vessels. It differs 

 chiefly from the definition of Distaplia in the form of the 

 colony, as well as in the ascidiozooids being embedded in the 

 test instead of forming prominent knobs or lobes. 



The following is the diagnosis of the new genus : 



Julinia, gen. nov. 

 Colony cylindrical, excessively elongated; ascidiozooids com- 

 pletely embedded in the fleshy or gelatinous test ; systems 



