428 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



Collecting records. — Point Lobos, Espiritu Santo Island, March 

 20, 1940, one specimen; Puerto Escondido, March 26, 1940, four 

 specimens. 



Family ISOPHELLIIDAE 



TELMATACTIS PANAMENSIS (Verrill) 



Figure 80, b, c 



Phellia panam^ensis Verrill, 1869, p. 440. 

 Phelliopsis panamensis Verrill, 1899c, p. 214. 



Sphincter alveolar, very elongate, whollj^ separated from the 

 endodermal muscles of the column (fig. 80, 5). Tentacles up to 

 96 in number; in contraction usually longitudinally furrowed; in 

 older specimens often somewhat knobbed, their longitudinal 

 muscles ectodermal. Two siphonoglyphs. Up to 48 pairs of mesen- 

 teries, 2 pairs of directives, 6 pairs perfect with filaments and 

 acontia and strongly restricted to almost circumscribed, often 

 reniform, strong retractors. Other mesenteries without filaments, 

 but the mesenteries of the second cycle, and sometimes those of the 

 third, have filaments and acontia. Filaments of these mesenteries 

 discontinuous with acontia, usually two, one on the upper side and 

 one on the lower of each piece of the filaments (fig. 80, c) . Num^- 

 ber of mesenteries somewhat more numerous than the tentacles. 

 Nematocysts of the tentacles (33.8) 39.5-42.3 by 2.5-2.8 ^, in 

 the largest specimen 50.8-70.5 by 2.8 /* (basitrichs) ; those of the 

 actinopharynx partly 22.6-31 by 2.8-3 fx, partly 12.7-18.3 by 

 1.5-2 fji (both basitrichs), partly (in the largest specimen) 25.4- 

 32 by 4.2-5.5 /t (microbasic ?9-mastigophors ?) ; those of the fila- 

 ments partly 12.7-22 by 1.5-2 ^ (basitrichs), partly 11.3-19.7 

 by 8.5-4.2 fx (microbasic p-mastigophors) partly 38-60.6 by 8.5- 

 11.3 (microbasic amastigophors) ; those of the acontia partly 

 (42.3) 52.2-66.3 (in the largest specimen 62-73.3 ix) by 8.5-12.7 /x 

 (microbasic amastigophors), partly 21-25.4 by 2-2.5 p. (basi- 

 trichs). (The nematocysts of the largest specimens are usually 

 longer than the smallest; the acontia have been examined in five 

 specimens, the tentacles in three, the actinopharynx in two, and 

 the filaments in four specimens.) 



Measurements. — Of the largest specimen from Point Lobos, 

 length 5.5 cm., greatest breadth 2 cm.; of the smallest specimen 

 from Point Lobos, length 1.1 cm., breadth 0.5 cm.; of the largest 

 specimen from Puerto Escondido, length 5 cm., breadth 2 cm. 



Collecting records. — Point Lobos, Espiritu Santo Island, March 

 20, 1940, four specimens ; Puerto Escondido, March 26, 1940, eight 

 specimens; Coronado Island, two specimens; Puerto Refugio, 

 April 2, 1940, one specimen. 



