lo8 A(^TINI.K OF ALBATWc^SS l:XPr,(M^\ TIONS :\[''MrHHU'H. 



towards tlio intranu'st'iitcrial spaco, except in the casi' of two pairs, 

 the (liroi'tivi's, situated at the extremities of the sagittal axis of the 

 stoniatoda'imi. whose lonuitndinal imiseles are on the faces of the me- 

 senteries whieli h)ok towards the adjacent interniesenterial space. 

 In a(hlition to these prinniry mesenteries secondary mesenteries are 

 also present; of these there nuiy be one on each side, situated in the 

 sulcuhvlateral interniesenterial space, or a pair on each side in tlie 

 same interniesenterial space, or tw«) pairs on each side in the sulculo- 

 lateral and lateral internu'senterial spaces. The dcM-lopnient of tlie 

 mesi'uteru^s is n]>on a bilateral i>lan. 



tJonus ORACTIS, ii«n. iio\ . 



Protactiniu' with twenty ines«'nteries, twehe of whicli are i)riniary, 

 and two jiairs on each side, in the sulculo lateral and lateral interme- 

 senterial chambers respectively, secondary. Oidy the eii»ht primiuy 

 mesenteries c(»rres}>omlini:' to the Ethcardsiti mesenteries, are ix'rfect, 

 gonophoric. and i)rovided with mesenterial tilaments. 



2. Oractis Diomedeae, sji. unv. 



I'lat.' \i\. Fiiis. r.-S: I'hite \\. Figs. 9-\\. 



No. Tl'T. Station L'8:5;t. J. at. o.'i- 08 N.; loiiji. U8 »0 W. Ui'i.tli. Ill latlioiua. 

 SoM-ral spt'i'iuuMis. 



All the specimens are contracted extensively (PI. xix. Figs. 5 and 0), 

 anil measuie in this comiition ."> to 8""" in height and 10 to l.S""" in 

 diameter. The base and colnnni are colorless and translucent, allow- 

 ing the internal organs to show thnnigh, but sections show that the 

 disc and tentacles have yellow ])igment granules in their ectoderm, and 

 probably in the living eondirion they had a more or less decided yellow 

 coloi". 



The base is more or less ronmled ^IM. xix. Fig. r))and passes directly 

 into the column, there being no limbns. The column is marked by 

 twenty longitudinal grooves corresponding to the insertions of the 

 nu'senteries. At tlie summit of the contracted animal ten tubercle-like 

 processes can be seen surroniuling the entraiu'C into the cavity con- 

 taining the contracted tentacles, and in sections tlu'se tubercles may 

 be seen (I'l. xx. Fig. 11, tii\ to be «lue to thickenings ot" the mesoghea. 

 In some ot" the spt'cinu'us tlu'y api»ear to be intbhU'd along with the 

 tentacles. 'I'he ectodiMui of tlu' <'olumn wall has entirely disappeared. 

 Tin' mesoghea is thin, and mort> or liss tibrillar in structure with com- 

 jtaratively few cells. The sphincter nuiscle is ot' the ditVuse typi' (PI. 

 XX, l-'ig. 11.^. its mesogheal processes being long an»l niunercuis, so 

 that a lairly stnuig muscle is i^iodmcd. 



The tentacles a])pear to be ten in number, 'fhey an> rather short, 

 cylindrical, obtuse. In transverse sections it is seen that tlieir longi- 

 tudinal nniscles are conlhu'd to the ectoderm, and for tlu luost part are 



