130 Transactions. — Zoology. 



important characters of P. baJeeri, in which it seems to 

 resemble the present species, and to differ markedly from 

 other Perichcetce. In any case, therefore, it seems to be 

 desirable to draw the attention of zoologists to this earth- 

 worm, as it seems to connect the genus Perichceta with other 

 forms. The most remarkable structural peculiarities of P. 

 intermedia concern the excretory and reproductive organs. It 

 is a moderately large species, being stout in proportion to its 

 length ; its general aspect is very different from that which is 

 characteristic of Perichceta; the setae are not at all con- 

 spicuous, and the worm has a smooth, somewhat glandular 

 appearance. This seems to be due to the absence of a ridge 

 in the middle of each segment for the implantation of the 

 seta?.. The buccal lobe does not divide the peristomial segment. 

 The clitellum was not developed in either of my two speci- 

 mens. The setce form a nearly complete ring round each- 

 segment, only failing for a short space in the mid-dorsal 

 and mid-ventral lines. There are no dorsal pores. In the 

 neighbourhood of the male genital pores are a number of 

 papillae. The male genital yores are a pair of slit-like orifices 

 on the eighteenth segment, on a line with the setae, which 

 are almost absent in the space between the two oriiices, 

 there being apparently only one seta on the inner side of the 

 pore. The oviducal pores are paired, and upon the fourteenth 

 segment ; this is unusual, but is occasionally met with in the 

 genus Perichceta. The common arrangement is a single 

 median pore. The nephridiopores are quite obvious upon most 

 of the segments, and lateral in position. 



" Alimentary Canal. — The gizzard is situated in the fifth 

 segment ; it is very small, and the muscular walls not very 

 thick. The oesophagus is furnished with separate calciferous 

 glands in segments x. and xi. These glands are not, as is so 

 often the case, connected with the lumen of the oesophagus by 

 a narrow duct ; they present the appearance of swellings of 

 the oesophagus, and resemble very closely the calciferous glands 

 of Microchceta (Beddard, Benham). Though probably formed 

 as two-paired outgrowths of the oesophagus, no trace of a 

 paired arrangement is visible in the adult worm . The n&ph ridia 

 are paired ; the funnels, as is nearly always the case, open 

 into the segment exterior to that which bears the external 

 orifice. I reserve for the present details as to the structure 

 of the nephridia. 



"Genital Organs.— The sperm-sacs are in ix., x., xi., and 

 xii. The vasa deferentia open into segments x. and xi. ; the 

 two vasa deferentia unite to form a single tube, the relations 

 of which with the atrium I have not been able to make out 

 with certainty. I believe, however, that it does not open on 

 to the exterior independently of the atrium ; there are no 



