228 J. H. OETON, 



COERELATION IN THE CHARACTERS OF THE GONAD AND 

 AMBULACRA IN THE GENUS CUCU MARIA. 



The difference in the character of the gonad in C. saxicola and C 

 norniani described in the foregoing pages suggested that similar differ- 

 ences might occur in other Cucumarians. On investigating the other 



y .< <-M-^ r. A i — -^^^ ^?s 





Fig. 9. — View of Cucumaria sa.ricola, showing the five ambulacral rows ( X f ). 



The view is mainly lateral from the right side, but the jDosterior end of the 

 animal is turned somewhat dorsalwards to show in this region the three ventral 

 ambulacral rows. These rows are seen to consist of suctorial tube-feet. On the 

 upper right side of the figure are seen the two dorsal ambulacra, the right one 

 of which is continued in profile to the posterior end of the body ; both rows are 

 seen to consist merely of ambulatory papillae, except at the anterior end, where 

 there are a few suctorial tube-feet. 



species of this genus occurring in this district, it was found that they 

 fall into two groups, having the following characters : — 



Gkoup a. Species whose gonad consists of numerous short cylindrical 

 tubes, and whose dorsal as well as ventral ambulacra 

 have well-developed tube-feet. 

 In this group fall the species normani, liyndmanni, elongata. 

 " (Compare Fig. 10, p. 230.) 



Group B. Species whose gonad consists of relatively few, large, club- 

 shaped tubes and whose dorsal ambulacra contain mostly 

 ambulatory papillae, which are less numerous than the 

 tube-feet in the ventral rows, but with a few definite 

 tube-feet at the anterior ends. (See Fig. 9, p. 228.) 

 In this group fall the species saxicola and hrunnea. 



Now the genus Colochirus differs in the literature (9, p. 343) from the 

 genus Cucumaria mainly in having ambulatory papillae in the dorsal 

 ambulacra. It is possible, however, that when the gonad in species of 



