C70 THE MARINE ANNELIDES OF THE ORDER SERPULEA, 



more nearly equal than is usual in this family, and, when retracted, 

 the former may appear even decidedly shorter than the latter. The 

 branchiae which are eight in number, have short stems with two 

 rows of pinnules, and are devoid of terminal dilatations or pseud- 

 opercula. The collarette and the lateral flaps are not very greatly 

 developed. The thorax possesses nine segments, of which the 

 first differs from the rest in the form and size of the setaa, and in 

 the absence of ventral pectines. The abdomen possesses nineteen 

 segments with long acicular setae ; the anal segment presents a 

 a pair of very prominent rounded ciliated anal appendages. 



The setaa of the first segment are -5th of an inch in length ; they 

 are slightly geniculate near the extremity, the genu being armed 

 with a small number of teeth. The remaining thoracic setaa are 

 very obscurely spathulate, being slightly expanded near the fine 

 tapering point. The abdominal setaa are all extremely fine simple 

 hairs, o^th of an inch iu length. In the thorax there are 25-32 

 pectines in each neuropodium ; in the abdomen the number is 

 much smaller, diminishing from ten in the anterior region to five 

 in the posterior — the last two or three segments having none at 

 all. The general colour ie very light pink, with a number of 

 minute crimson dots on the head. 



This species is closeby allied to the Salmacina aedifieatrix of 

 Claparede, and seems to form a connecting link between it and the 

 Protula Dysteri described long ago by Huxley. From the latter it 

 differs in the absence of any pseudopercula or terminal dilatations 

 of the branchiae ; from the former in the form of the thoracic sette 

 and other minor points. 



The slightly spathulate form of the thoracic setaa does not seem 

 to be of sufficient importance to justify a separation of the 

 Australian species from its closely related European allies, 

 though " Setaa spathulataa vel pectinatse in abdomine desiderata)" 

 is given by Claparede (1), as a diagnostic peculiarity of the 

 genus. 



I was much interested to observe that the Australian species, 

 like Salmacina Dysteri, as first noticed by Huxley, is herma- 



(1) Ann. Ch<5t. Supp., p. 154. 





