BY N. A. COBB. 399 



never been seen in Chromadora. In some members of Monhystera 

 the male coils himself around the female once or twice, so that in 

 that genus the ventral row of minute glands may serve to keep 

 him from slipping. The same is almost equally probable in 

 Chromadora. These statements are necessarily cautiously made, 

 but I believe they rest on a firmer basis of observed fact than any 

 previous remarks on the same subject. The two equal spicula are 

 apparently of uniform size throughout, but are not so in reality. 

 There is an anterior thin and less conspicuous part, which easily 

 escapes observation, and which, taken together with the more con- 

 spicuous shaft, causes the organ to have somewhat the form, when 

 seen in profile, of a segment of a circle. The distal three-fifths of 

 the more conspicuous part, i.e., the shaft, is slightly arcuate. The 

 proximse are not expanded. The entire length of each spiculum 

 is considerably greater than the anal body-diameter. Arranged 

 parallel to the spicula are two accessory pieces, two-thirds as long 

 as the spicula themselves. The blind end of the single straight 

 testicle is situated as far behind the cardiac constriction as the 

 latter is behind the anterior extremity. The ejaculatory duct 

 begins somewhat anterior to the row of supplementary organs. 

 The spermatozoa are of such a size that six side by side would 

 reach across the oesophagus. 



Hah. — This little worm was very common among algse in Port 

 Jackson, New South Wales, Australia, 1893. 



Y. Platycoma, new genus. 

 P. CEPHALATA, n.sp. Female unknown. 



•8 4- 15- — M— ^^ 97-6 ^, , , , , . , . 



7^^ — rg rg ^ :y 97 mm. ihe smooth and rather thni skin 



bears hairs throughout the length of the animal, but these are 

 inconspicuous except on the head and anterior part of the neck, 

 where they are long and slender. The neck is cylindroid, diminish- 

 ing suddenly at the head. The latter is rounded in front, and is set 

 off from the neck by a broad and shallow constriction. There are 

 ten cephalic setse of equal size arranged in the usual manner, one 

 being situated on each lateral line and two on each submedian 



