NO. 5 fraser: hydroids 207 



Glytia exilis, new species 

 Plate 24, Fig. 5 



Trophosome. — Colony, 8 mm, lax, slender, and appearing more 

 slender than it really is because of the large size of the hydrothecae and 

 gonangia, growing from a filamentous stolon ; although the colony may 

 be quite erect, the stem does not pass up continuously in the same direc- 

 tion ; the basal portion continues to form a long pedicel for a hydrotheca ; 

 where it passes into the pedicel, the next section of the stem is given off, 

 which in turn gives rise to the pedicel of a hydrotheca, or of a gonangium ; 

 the next section of the stem arises from this, etc. The pedicel of the 

 hydrotheca is long, 2 mm or more, but that of the gonangium is quite 

 short. There are several annulations at each end of the long pedicel, 

 usually more of them proximally than distally, several some distance 

 from the proximal end of each stem section, and others along the entire 

 length of the short pedicel of the gonangium. The hydrotheca is large, 

 the largest in any American species of the genus, 1.2 x 0.43 mm, gradually 

 and regularly increasing in diameter from base to margin; there are 12 

 sharp, deeply cut teeth on the margin. 



Gonosome. — ^The gonangium is large, 1.4x0.35 mm, among the 

 largest in American species of the genus; it is nearly cylindrical, but it 

 tapers somewhat from the middle to the more slender base, and very 

 slightly towards the distal end, although there is a slight expansion at the 

 margin. The surface is smooth. 



Distribution. — Station 1274-41, 3^^ miles south of Hueneme, Calif., 

 29-30 fathoms. 



Remarks. — The colony of C. exilis bears much resemblance to that 

 of C. macrocarpa Fraser, obtained far away, off the coast of Peru. The 

 arrangement of the stem and pedicels is quite similar, and the annulations 

 appear in the same areas, but C. macrocarpa is a more delicate species ; the 

 hydrotheca is somewhat the same shape but is not nearly so large; the 

 teeth are not so numerous, and not so deeply cut. The gonangium is 

 similar in size, but the longitudinal, wavy lines, characteristic of C. 

 macrocarpa, are not present in C. exilis. In this species, the resemblance 

 to the gonangium in C. cylindrica is much more definite. 



Unless or until further collection can close the geographical gap 

 between the two species, C. exilis and C. macrocarpa, it would not be 

 wise to consider very close relationship. 



