THE COAST OF CALIFORNIA. 139 



are not close, for while one has a colonial capitulum the 

 other has but a single polypide to each stem. 



A possible interpretation of the combination of structural 

 features which we have in Ascorhiza is that the genus be- 

 longs to the Ctenostomata somewhere near Alcyonidium, 

 but that it possesses a sensitive, flexible jointed stem, a 

 feature very rare in this group. It seems probable also 

 that this stem is homologous to the stalk of Urnatella, a 

 fresh-water genus, and more distantly related to a barrel- 

 shaped structure at the base of the peduncle of Ascopodaria. 

 If these comparisons are borne out by more intimate knowl- 

 edge of Ascorhiza and it is found that there is a true ho- 

 mology between the structures in question it may be found 

 that we have in Ascorhiza a genus connecting two great 

 groups of Bryozoa to which the genera mentioned above 

 belong. So characteristic are the structural peculiarities 

 of Ascorhiza, and so different from any known genus, that 

 it may be necessary to make a new family for its reception. 



From my limited knowledge of the internal anatomy, es- 

 pecially of the relative positions of the oral and anal aper- 

 ture, I am unable to discuss this important anatomical 

 feature in my reference of the genus to Ctenostomata or 

 Cheilostomata. The external features alone stamp it as 

 different from any known genus of either group. 



NUDIBRANCHIATA. 

 CABRILLA gen. nov. 



At the time of my visit to Santa Cruz Island, the an- 

 chor of a buoy in Prisoner's Harbor was pulled up and 

 with it came a new genus of Nudibranchs for which the 

 name Cabrilla is suggested. 1 



1 From Cabrillo, the intrepid discoverer of the Santa Barbara Islands. 

 ESSEX INST. BULLETIN, VOL. XXI 10 



