88 DISCOVERY REPORTS 



1918, p. 393) point out the considerable resemblance of C. diiplicata to C. lativentris, but the present 

 specimens are certainly entirely different from lativentris, and I think we may safely refer them to the 

 species, diiplicata, described by Maas. 



Description of an adult specimen (St. 1974) (PI. VI, fig. 5): Diameter 50 mm. Umbrella flat, 

 the jelly (as preserved in formalin) rather thin and soft; 27 tentacles in different stages of development. 

 The oral wall of the stomach has almost entirely disappeared, but the outlines of the gastric pouches 

 are undamaged. When fully developed, the gastric pouches are tongue-shaped or rectangular, some- 

 what longer than broad, with parallel sides, separated by spaces of about the same width. The gonads 

 form a continuous, folded band following the edge of the stomach with its gastric pouches uninter- 

 ruptedly. The lateral parts of the peripheral canals are very broad, usually broader than the inter- 

 radial spaces between them, of equal width throughout their length, about two-sevenths as long 

 as the radius of the umbrella. The distal, transverse part of the canals is narrow. The fully developed 

 tentacles issue from the terminal ends of the gastric pouches ; the endodermal tentacle roots are bent 

 sharply downwards and usually invisible from above. In this specimen all the tentacles are strongly 

 contracted and fairly short, reaching only slightly beyond the margin of the umbrella. Several of the 

 tentacles are small (young) and more or less widely separated from the corresponding gastric pouches, 

 which also are smaller than those corresponding to the fully developed tentacles. The peripheral 

 canals flanking the young tentacles are also narrower than the others. In about one-third of the cir- 

 cumference of this specimen, young and fully developed tentacles alternate regularly. Further remarks 

 on the development of the tentacles and gastric pouches will be given below. There are two or three 

 sensory clubs on each of the marginal lappets, and the otoporpae are very small. The peronia are 

 very narrow, and in the marginal zone the lappets are separated by very slight indentations. The 

 velum is much torn and mutilated. According to a note on the label, the peripheral canal was milk 

 white in colour, otherwise the specimen was transparent and colourless. 



Remarks on other specimens 



Young stages. Even very small specimens may safely be referred to this species on the basis of 

 the gastric pouches, which are elongated, rectangular with parallel sides, as wide as or somewhat 

 narrower than the interradial spaces between them. The youngest specimen is only 4 mm. wide 

 (St. 699) and has 9 narrow gastric pouches and 9 tentacles of equal size, with no indication of addi- 

 tional tentacles developing. A specimen 5 mm. wide (St. 1370) has 8 fully developed tentacles and 2 or 

 3 small ones. Three specimens from St. 282 are of particular interest. One of them is 7 mm. wide 

 with 10 tentacles of equal size, each of the ten lappets has a slight median incurvation with a tiny rudi- 

 ment of a tentacle; in this specimen the oral wall of the stomach is retained and has a small circular 

 mouth opening. The two other specimens from St. 282 are somewhat further developed; one of them 

 is 8 mm. wide with 9 fully developed and 8 very small tentacles, the other is 10 mm. in diameter with 

 1 1 fully developed tentacles and 9 small ones, a little larger than in the preceding specimen. In both 

 specimens the gastric pouches correspond in size to the tentacles, and these specimens are very 

 similar to the one described and figured by Maas. In subsequent stages the addition of new tentacles 

 and gastric pouches proceeds irregularly, and the number of small tentacles is always less than that of 

 the fully developed tentacles. 



The development of additional antimeres is illustrated in PI. VII, fig. i. The specimen (St. 100) 

 is 29 mm. in diameter and has a total number of 23 tentacles. In the marginal lappet between two 

 fully developed tentacles (to the left of the figure), the transverse part of the peripheral canal has 

 formed a small centripetal sling, narrow and pointed ; the two parts of the sling are close together, 

 forming a narrow groove which will become the future peronium, and at the end of this groove a 



