172 ACTINLK oK AI>I!A'I'U()SS EXPLORATIONS .Af' MURRICH. 



Tlicmoiilli is proiiiiiiciil. 'V\w siplioii(>j;l\ plios aic deep and long'er 

 tliaii till' stoiiiatixla'uiii. All (he iiu'sciitt'iit's, with the exception of 

 the yonu<>est <'yele, are peil'ect; there are apparently live cycles, the 

 mesenteries of the tliiid and fonith cycles beiny,- ,G;onophoric. The 

 mnsch' processes of the lonuitnilinal innscles are develojx'd ovei- the 

 entire nuiscle-bearini;- snriace of the niesentery, increasing;' slightly 

 towards the inner edi^-e of this snrface ((► form a^ weak i)ennon. lu the 

 npi)er ])art of the mesenteries, above the region where (he })arieto- 

 basilar occurs the ])arie<al |>art of the mesentery is somewhat thick- 

 ened, and the nniscle processes in Ihis liiickened region are somewhat 

 more numerous and nu>re slendei- than elsewhere (PI. xxvii, Figs. (J2-G3). 

 Over the general surface of the mesenteries the processes are com- 

 paratively stout (PI. XXVI I, I'Mg. (!1). The parieto-basilar muscle pre- 

 sents essentially the sanie characteristics as in .1. ludlo.sa, the mesoghea 

 in the region occupied by it having small cavities enclosed in it. As in 

 ^■l. valht.sa also a basal muscle is i)resent (PI. xx\ ii, I'ig. (iU), but it has 

 relatively but a slight development. 



(it'll IIS PYCNANTHUS, ticn. n..v. 



Paractidai of moderate size, with I hick, tlunigh rather soft, column 

 wall; no tuT)ercles or verruca-, though (lie ui)per portion of the column 

 is marked by more or less distinct longitudinal ridges lunniug to the 

 bases of the tentacles. JNIargin tentaculate, not lohed; tentacles short, 

 but slender, not swollen at the base. Sphincter muscle rather weak, 

 lying close to the en«loderiu. 



I have estiiblished this genus foi' the reception of a form whieh does 

 not seem to be assignable to any of the genera of Paracti(hc as they 

 arc here uiulerstood. Tlu» weak sphinctei- and slender tentacles ex- 

 (dude it from the genus AefiHOstolo; the absence of a marked dilata- 

 tion of the si)hincter and the occurrence of ridges upon the U])per i)art 

 of the column, running to the bases of the tentacdes, show it to be dis- 

 tinct from the genus P(( metis. The ridges are hoHow, with rather del- 

 icate walls, and iesend)le those found in certain Sagarti<ls which \^os- 

 sess a capitulum. The absencte of aeontia, however, ])recludes the 

 association of the form about to be described with the Sagartidie. 



20. Pycnanthiis inaliforniis, sp. nov. 

 ri. XXVII, Kins. Cil-(i7; I'l. x\\ in, Fif^. (>8. 



No. 728. Station 283i». Lat. :>8^ 08' N.; Ion-;-. 118 ' 10 W. D.ptli, HI (athoius. 

 Fourteen specimens. 



Thelargestspeeimens(ri. xxviT, Fig. (14), measure 2..V'" in height, and 

 3.1V"' in diameter. All are contracted, the tentacles and up])er por- 

 tion of the column being infolded. The alcohol in which they are pre- 

 served is stained a very distinct yellow, and w hen spccinu'us are plae.ed 

 in fresh alcohol this (piickly assumes ihc same coloration. The pig- 



