1896.] from: thh sandwich islands. ' 197 



throughout. On the very first seta-bearing segment oE the body 

 the setaj have precisely the same ridged free extremities that the 

 setae upon the clitellum show. At first the setse of each pair are 

 fairly close together. Lat«r they get farther apart and become 

 irregular in arrangement, as in Pontoscole.v corethrurus. On the 

 clitellum the ventral pairs are quite regular, although each indi- 

 vidual seta of the pair is farther away from its fellow than 

 anteriorly. This continues for a short distance behind the 

 clitellum. On the other hand, the lateral pairs of setae are irregular 

 in the clitellar region. The ventral of the two setaj, however, which 

 is on a line with the nephridiopore, is fixed in position : it is the 

 other which varies. 



The clitellum occupies segments xiv.-xxi. with a portion of xiii. 

 and xxii. 



The dorsal vessel is in certain respects peculiar'. "Where it 

 emerges from the last thick mesentery it is moderately thin ; it 

 gradually becomes thicker a,nd at the same time monihform ; the 

 increased thickness is due to the fact that the dorsal vessel 

 becomes double ; its character is that of the dorsal vessel in 

 AcantJiodnlus novce-zelandiw, i. e. the tube is single where it 

 traverses the septa, but separates into two halves between the 

 septa. In segments xiv. and xv. the dorsal vessel attains to its 

 greatest bulk ; after tliis its calibre becomes suddenly diminished. 

 It retains, however, its double character. 



lu segments xi., xii. are hearts which seem to have no con- 

 nection with the dorsal vessel but only with the supra-intestinal. 



The gizzard is in segment v. ; it is followed by tour very thick 

 septa. In the segments following the gizzard are 3 pairs of calci- 

 ferous glands. Behind the first three strong septa are very small 

 spermatothecae, simple elongate oval pouches without diverticula. 



Hab. Mauna Loa, Hawaii, and Waiahia, Oahu. 



Perichceta indica, Horst. 



Dr. Michaelsen has called attention '^ to the fact that this species, 

 which is very widely distributed, is frequently without a " prostate" 

 gland. In five specimens which he received from Georgia and 

 Florida there was no trace of the gland, only tlie muscular duct 

 being present. In the 6th specimen the gland was present on 

 one side. Dr. Michaelsen further makes the suggestion that the 

 original home of the species may be Japan, where as a general 

 rule ' the PerichcetcB show the same character. 



Among the worms collected by Mr. Perkins were 8 examples 

 of this species from Molokai, all fully mature ; I dissected seven of 

 them, in none of which was there the least trace of the gland in 

 question ; tlie curved duct alone was present. 



' In one specimen of three which I examined, the dorsal vessel seemed to be 

 single. 



'' " Die Kegenwurm-Fauna von Florida u. Georgia," Zool. JB., Bd. viii. 

 p. 177. 



' F. E. Beddard " On some Perichoetida) from Japan," ibid. Bd. vi. p. 75.5, 



