120 PROCEEDINGS OF THE ACADEMY OF [1889. 



muscle imbedded in the mesoglcea, and occupying nearly its whole 

 thickness. 



All the specimens were in a state of strong contraction, and I was 

 not able to see the tentacles. Duchassaing and Michelotti state 

 that they are small tubercles. My sections show that they are ar- 

 arranged in two cycles. It is also evident that they are short, 

 but they can scarcely be termed tnbercles. Their mesogheais thick, 

 especially toward the base, thinning out somewhat towards the apex. 

 Its outer surface is thrown into rather strong muscular processes. 



The surface of the stomatodpeum is thrown into numerous rather 

 high folds, the ectoderm being elevated on slender processes of 

 the mesoglcea. 



The mesenteries are arranged on the microtypus and number 

 twenty-two pairs. Towards their base the mesoglcea is very thick 

 diminishing gradually towards the distal edge. Just at the base 

 there is a sudden diminution of the thickness, so that they are 

 attached to the column wall by a thin pedicle. The basal portion 

 contains the usual canal, and in addition there are numerous lacunar 

 similar to those of the column wall in every respect. M. tuberculata 

 is hermaphrodite, and I am able to add this particular to the defini- 

 tion of the genus given by Erdmann. 1 I could not make out any reg- 

 ularity in the arrangement of the reproductive elements on the differ- 

 ent mesenteries, nor did there seem to be any definiteness in their 

 position in any one mesentery. Sometimes a mesentery would possess. 

 ova only, but usually each one presented both ova and spermatozoa. 



8. Corticifera ocellata (Ellis). 



Synon. : Alcyonium ocellatum. Ellis and Solander, 1786. 

 Palythoa ocellata. Lamouroux, 1821. 



A number of small colonies of a Corticifera were obtained at 

 Shelly Bay, and were accompanied by a label referring them to the 

 above species. The term ocellata was first given by Ellis and Solan- 

 der to a form which, however, was very poorly characterized, so 

 much so that certainty of identification is impossible. The only 

 statement in the description of which use may be made is that the 

 polyps are rust-colored. Later authors simply copied Ellis and 

 Solander's description until Dana, 2 evidently relying on the figure 

 which accompanies the earlier description adds the characteristic 

 that the polyps, though imbedded in coenenchyma throughout the 



1 Erdman A. loc. cit. 



-J. D. Dana, Zoophytes. United States Exploring Expedition. 1849. 



