90 PRONEOMENIA INSULARIS. 



succeeding portions. With the exception of a small mass of protoplasm contain- 

 ing the spherical granular nucleus the cytoplasm is charged with a product 

 apparently muciform, staining intensely with logwood dyes. In many cases 

 the material has been discharged leaving a relatively spongy protoplasmic matrix. 

 When relieved of their load the cells show no sign of degeneration but continue 

 to elaborate the secretion which forms as minute granules uniformly distributed 

 throughout the protoplasm. As these increase in amount they unite, finally 

 becoming one confluent mass that almost completely fills the cells. In the only 

 other specimen which was sectioned this portion of the gonoduct is composed of 

 cellular elements of the same appearance, but the secretion is hyaline and unaf- 

 fected by Delafield's haematoxylin, a condition of affairs due in all probability 

 to a different phase of glandular activity. 



In both specimens these cells of the anterior third of the shell gland blend 

 rather gradually with those of the succeeding section of the duct. As Hubrecht 

 notes in Proneomenia sluiteri the cells are very slender elongated elements with 

 basal nucleus and a secretion, developing at first in the form of minute granules 

 which subsequently fuse and form particles of larger size until one great droplet 

 occupies almost the entire cell often crushing the nucleus into an almost indis- 

 tinguishable mass. It is worthy of note that all the cells in a fairly well-defined 

 area are usually in the same stage of activity, perhaps discharging their burden 

 while those of neighboring regions may be entering into the first stages of the 

 process. In many cases where the secretion has recently been discharged it acts 

 as a highly viscous fluid that only gradually undergoes liquifaction and fills the 

 lumen of the cloacal passage. 



Proneomenia insularis, sp. nov. 



This species is represented by a small portion of the anterior end of one 

 individual including the radula and the comparatively long ventral salivary 

 glands. 



The specimen was found in the bottom of a jar containing some alcyonarian 

 corals that were dredged near Bird Island (Sta. 4157) at a depth of 762-1,000 

 fath. where the bottom consisted of white mud and foraminiferous sand with a 

 temperature of 38°. In external appearance and especially in the relations 

 and structure of the cirri, atrial ridges, the radula, salivary glands, and other 

 of the more important organs this species shows a verj' close resemblance to the 

 species of Proneomenia just described; accordingly I have very little hesitancy 

 in placing it in this genus. The present fragment, cylindrical in cross section 



