30 Proceedings of the Biological Society of Washington. 



the distal dark portion being decidedly hollowed out, almost suggesting a 

 basal joint of Bankia. Of the animal we may say that the siphons are of 

 unequal thickness but almost of equal length. They are tipped with num- 

 erous rose colored spots. They extend about half the length of the spatu- 

 late portion of the pallettes, and are split to the base of the spatulate por- 

 tion. A broad collar in the shape of a membrane surrounds the stalked 

 portion of the pallettes and extends down over the rest of the animal for a 

 length equal to the exposed part of the siphons. 



The type, Cat. No. 341,155, U. S. N. M., was collected in San Pablo Bay, 

 California. It measures: height, 5.5 mm.; length, 6 mm.; thickness, 7 mm. 

 The pallettes measure: length, 5.5 mm., of which 2 mm. go to the stalk; 

 width, 2 mm. 



Thanks to the help of Captain Edward L. Beach, the Commandant of 

 the Mare Island Naval Station, who placed at my disposal the necessary 

 equipment for extracting and examining infested pilings, I was able to make 

 a large collection of this species, which has been causing the extensive rav- 

 ages in San Pablo Bay and the adjacent region in recent years. I therefore 

 take great pleasure in naming this species in honor of the Captain. 



Teredo (Teredothyra) dominicensis, new species. 



Shell subglobular, compressed, cream yellow, the extreme anterior portion 

 bearing a notch whose external border is reflected as a smooth fold over the 

 outer portion of the shell, but not appressed to it. Immediately back of 

 this are the dental ridges, which appear to radiate more or less fanlike from 

 the anterior margin. They are closely crowded at the anterior margin, but 

 become regularly more distantly spaced as they pass from the anterior to 

 the posterior termination. At the latter place they are about two and a 

 half times the width of the ridges. These ridges are exceedingly finely 

 denticulated at their free margin; thirty-four of these are visible, but this 

 is not all, for the earliest are partly covered by the anterior reflection, and 

 some have probably been lost by the erosion of the umbones. These ridges 

 join the dental ridges of the anterior median portion in a little more than a 

 right angle. The latter are very closely crowded, the spaces between them 

 being mere impressed lines. The dental ridges of the anterior median por- 

 tion are a little more strongly denticulated than the dental ridges on the 

 anterior portion. In about the middle of their length they separate from 

 their closely packed condition, taking a decidedly backward slant on the 

 early portion of the shell, and a lesser angle on the last portion The middle 

 of the median portion is but a roughened groove, which extends from the 

 umbone to the ventral margin. The posterior portion is about twice as 

 wide as the anterior median, and is marked by rather strong lines of growth. 

 In fact, it would almost seem as if the attenuated dental ridges, after bend- 

 ing over the median groove, continued as smooth raised threads over the 

 posterior median portion. The median portion, compared with Teredo in 

 general, is rather narrow. The posterior portion forms a moderately large 

 auricle which on the external surface is marked by lines of growth and a 

 few roughened ridges. The interior of the shell is bluish white. The um- 



