20 ANTARCTIC MARINE 



as do the ganglion cells near the nerve-ring. These two neuclei probably indicate 

 the presence of two nerve cells. They are best seen in the dorso-ventral view. The 

 refractive elements of the lining of the oesophagus, especially in certain aspects 

 of the head, appear to extend into. the pharynx in a peculiar way, as shown in the 

 sketch. The rectum is more or less prominent, and in the male the anus is raised. 

 The tail tapers in such a manner that at the middle it is one-third as wide as at 

 the anus. Its terminus is slightly swollen. Caudal setae appear on the base of the 

 tail. 



The vagina extends inward nearly at right angles to the body wall, about half 

 way across the body. The uterus, three to four times as long as the body is wide, 

 contains spermatozoa one fifth as wide as the body. The posterior, rudimentary 

 branch of the uterus, nearly twice, as long as the width of the body, also contains 

 spermatozoa. The eggs are nearly twice as long as the body is wide, and one-third 

 as wide as long. The broad tapering ovary contains about twenty ova arranged 

 single file, and as many more packed irregularly in the distal fourth. 



The brownish, rather slender, uniform, acute spicula are one and one-third 

 times as long as the anal body diameter. The framework of the spicula is more or 

 less strong, and the proximal ends lie opposite or a little dorsal to the body axis. 

 The single, rather straight and rather frail accessory piece is of a simple character, 

 and has a backward pointing apophysis one-sixth as long as the anal body diame- 

 ter. The male presents the peculiarity of possessing two testes, an uncommon 

 thing in Monhystera. They are rather wide and of unequal size, the anterior, 

 more or less cylindroid one being considerably the wider. The blind end of one 

 testis is at the cardia, that of the other about one tail-length in front of the anus. 



Habitat; remarks. Cape Royds; Bay, Cape Royds; Bay. Seven females and 

 six males, somewhat shrunken. The specimens from the various localities differ 

 slightly in (1) the size and form of the cephalic setae, (2) the length and width of 

 the spicula, (3) the prominence of the amphids, (4) the prominence of the striae 

 on the tail. Diatoms and other unicellular organisms were seen in the intestine. 



11. Monhystera septentrionalis, n. sp. The lips are confluent. The lining of 

 the oesophagus is rather prominent, and one-fifth as wide as the oesophagus itself. 



33 The small and inconspicuous, some- 



- u ' y ~ E6 83- .5mm. what ellipsoidal caudal glands are 



1-9 arranged in a loose tandem in the 



anterior half of the tail. The anus is continuous. The conoid, 

 rather muscular vagina is one and one-half times as long as the body 

 diameter. The eggs are elongated, twice as long as the body is 

 wide, and less than half as wide as long. About thirty ova occur in single file in 

 the gently tapering ovary. 



Habitat; remarks. Bay, Cape Royds. Seven good female specimens. The 

 amphids are often a little farther back than illustrated. 



12. Monhystera meridiana, n. sp. The striae, about 1000 in number, are respon- 

 sible for a somewhat crenate contour, more noticeable near the tail. The strongly 

 developed cardiac region, set 



off by a constriction on each 

 side, is as wide as the intestine, 

 and forms a small but distinct 

 segment of the alimentary 

 canal. The vulva is elevated. 

 Eggs twice as long as the body 



