550 HTATT'S REVISION OF THE 



sliort fibres, rendering the intermediate tissue vesicular. The primary fibres are all single, 

 aud generally colored a darker shade than the secondary fibres, which are often quite 

 white. They project considerably as sharp, single sjDines, above the surface. The macera- 

 tion of this specimen was very complete, the whole of the interior being encrusted with 

 coral sand. 



Loc, Cape Florida, in Soc. Coll. 



Another specimen from Havana, in Coll Mus. Comp. Zoology, is intermediate in the 

 character of the skeleton between the last and true " cartilaginea." In some parts of this 

 the broad flabellate aspect of the primary fibres obtain, and they are arranged in lines, or 

 ridge-like projections on the surface ; whereas in other parts the primary fibres are single 

 and with connecting tissue form regular, four, five or six sided cells, as in the Cape Florida 

 specimen. The observer needs to be on his guard in the examination of this species, since 

 in some specimens the spicules taken into the cores of the fibres, both primary and second- 

 ary are all of one kind and quite whole, except here and there where they have been bent 

 too suddenly. 



Hircinia purpurea Hyatt. 



Spongia rubens Duch. et Mich., Op. cit., pi. x, fig. 1. 



This species is not the Spongia rubens as figured by Esper or described by Schmidt as 

 Pachychalina rubens, but is unquestionably identical with the species described by Duch. et 

 Mich. The specimens I have seen are all possessed of simple cylindrical branches, remind- 

 ing one decidedly of the ordinary ChaUnula oculata of this coast, both in form and in the 

 aspect of the surface. This impression can only be dissipated by the minute examination of 

 the skeleton. The fibres resemble those of IT. cartilaginea in their flatness, the aspect of the 

 horny matter which is essentially fibrous, the concentric arrangement of the fibres being 

 in many cases hardly distinguishable. There is a peciiliar irregularity in the shape of the 

 fibre, due to the ridges formed in tlie centre by the greater shrinkage of the sides. The 

 primary filares are arranged symmetrically in a radiatory manner and somewhat widely 

 separated ; the secondary fibres are at right angles and connected by a horizontal series of 

 fibres, which on the surface form a ditellian veil of a rather loose texture. 



Dr. Palmer reports this sponge as habitually growing upon other sponges, corals or gor- 

 gonite, and as quite uniform in its aspect. It dries readily, and the skeletons, even in 

 specimens dried without being macerated, permit the light to pass through them, as in 

 ChaUnula oculata. The color when living is purple. 



Loc, Florida and Nassau, in Soc. Coll. ; Pacific Ocean, U. S. Ex. Exp., in Coll. Acad. 

 Nat. Sciences, Philadelphia. 



CERATELLAD^. 



Dr. Gray describes this family in the Proc. Zool. Society of London, in the volume for 

 1868, from two specimens which he respectively refers to two genera, Dehitella and Cera- 

 tella. They are certainly very remarkable sponges, and undoubtedly, in spite of their 

 form and the extreme regularity of their skeletal structure, must be placed in the sub- 

 order of the Sponginse. The fibres are solid, and contain no foreign matter, or spicules. 

 The fibres are large in proportion to the size of the stems, and very closely united, so that 

 it is difficult to distinguish them into primary, or vertical and secondary, or horizontal 



