444 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



show a tendency to transverse stratification. I have sectioned 

 sphincters of individuals from all localities ; they agree rather well. 

 In figure 84, h, I have drawn the sphincter of a specimen from 

 Puerto Escondido ; the muscle meshes are usually a little larger in 

 other specimens. The tentacles are small, their spirocysts are few or 

 almost absent. The siphonoglyph is indistinct. The mesenteries 

 vary from 48 to 57 (26 + 32 ; 28 + 24 ; 28 -f 26 ; 31 -f- 26) . They 

 are thin, provided with a wide canal in the outer, swollen part ; in 

 their inner parts there are no canals or very few. Their muscles 

 are distinct but form no pennons. The nematocysts of the scapus 

 are 15-18.3 by 5.6-7 [x (holotrichs) ; those of the tentacles 13.4- 

 18.3 by 5.6-7 fx (holotrichs) ; those of the actinopharynx partly 

 14-18 by 3.5-7 /j, (holotrichs), partly 15-18.3 by 3-4 fi (microbasic 

 6-mastigophors) ; those of the filaments partly 14-19.7 by 5.6-8.5 /x 

 (holotrichs), partly 17-24 by 4.2-5.6-8.5 /x (holotrichs), partly 

 17-24 by 4.2-5.6 /x — in the specimens from Concepcion Bay, nar- 

 rower, 2.5-3.5 IX (microbasic 2>-mastigophors) . Specimens from all 

 localities were examined. 



Color. — The living colony from Concepcion Bay was blue-green. 



Measurements. — Polyps in contracted state, length up to about 

 0.9 cm., breadth up to 0.4 cm. 



Collecting records. — Puerto Escondido, on rocks, March 26, 

 1940, two colonies ; Coronado Island, March 27, 1940, four colonies 

 on fragments of lime; Concepcion Bay, March 27, 1940, two 

 colonies. 



Additional distribution records. — Pearl Islands, Panama. 



Remarks. — I have with some doubt identified the specimens with 

 Z. danae, though the color of the specimens from Concepcion Bay 

 indicates that they may be referred at some time in the future to 

 Mamillifera (= Zoanthus) nitida, described by Verrill (1869, p. 

 497). 



I cannot understand Verrill's statement that there are 27 small 

 tubercles inside the bases of the inner tentacles and opposite the 

 outer tentacles. The species may be a Zoanthus as "the basal mem- 

 brane and surface of the polyps are smooth and soft, without any 

 adhering sand." Andres thinks that the tubercles are "brattee" 

 but these do not occur in Zoanthus. 



ZOANTHUS DEPRESSUS, new species 



Figure 84, i 



Owing to the very scant material available I can give only a very 

 short description of this species, but it is certainly different from 

 Z. danae. The small colony consists of a mother polyp and two 



