^ g DISCOVERY REPORTS 



Spicules generally are dark, almost blood red, and the more inflated the specimen is, the more pinkish 

 it becomes, whereas strongly contracted specimens like that from St. 2633 are dark red especially on 

 its leaves and rachis. In such specimens, however, the longitudinal dorsal white band along the rachis 

 is extraordinarily obvious and comparatively broad. In the specimen from St. 2633 the 5 cm. long 



stalk is yellowish white. , 



At a first glance this strongly contracted specimen recalls P. phosphorea f . vanegata. Earlier authors 

 like Kiikenthal and Broch (191 1) have generally emphasized the spongy tissues of P. rubra, which 

 enables it to extend markedly, but nobody seems on the other hand to have hinted at its strikingly great 

 faculty of contraction. This power is comparable with that of Pteroeides griseum (comp. Niedermayer 

 iQi I) In Pennatula the colour is confined to the spicules, and the shade of the colour of a specimen 

 will therefore depend to a great extent upon its state of dilation or contraction. This was easily seen in 

 the 10 specimens from the Discovery collections, the specimens of which were very differently 



expanded. 



P rubra is characterized in the literature as a Mediterranean species. Looking at the tew localities 

 which are sufficiently precise to plot on a chart (fig. i, p. 249), the species, like Cavernularia elegans, 

 (p. 250) seems to belong zoogeographically to the same group as Veretillum cynomormm; more 

 localities are recorded from the Atlantic Ocean than from the Mediterranean. Like V. cynomorium 

 also, Pennatula rubra seems to have its eastern border in the Mediterranean oflt southern Italy; along 

 the eastern coasts of the Atlantic, it is distributed from Portugal and southwards to Angola, and its 

 bathymetric range lies between 60 and 230 m. depth. 



PTEROEIDIDAE 



Pteroeides griseum (Bohadsch 17 



^.t"*. 



\J A. 



) 



(Synonymy before 1910, see Kiikenthal and Broch, 191 1) 



P. griseum Kiikenthal 1915, p. 98, figs. 104-7. 



P. griseum Hickson 1916, pp. 219 et seq. 



P. spinosum Pax & Miiller 1953, p. 31. 



P. griseum Broch 1953, p. 15. 



P. spinosum Pax 1956, p. 59. 



St. 2634, 12° 17-4' S, 13° 31-3' E, 80-91 m. I specimen, total length 20 cm. 



The specimen is rather strongly contracted, although its total length is 20 cm. However, the total 

 length (or height) of a specimen of Pteroeides is rather problematical, because of its enormous faculty 

 of inflation and contraction. This is easily observed in aquaria. By night I have observed specimens of 

 P. griseum, the raches of which have expanded to about i ft. in height above the mud with a breadth of 

 4-5 in., whereas by day the same specimens had contracted to a length of 4-5 in., only a couple of 

 inches broad, and all but entirely buried in the muddy bottom; in this case the leaves were moreover 

 packed against each other along the stem. 



Most authors have admitted two varieties of P. griseum, var. longispinosum and var. brevispinosum 

 (see Kiikenthal 191 5, p. 99). The Discovery specimen is of special interest in this connexion. Most of 

 its leaves belong to the brevispinosum type, but some of them are decidedly of the longispinosum type. 

 This supports Kukenthal's (191 5) words, that the two varieties instituted by KoUiker 'nicht scharf 

 getrennt sind '. 



Hickson (191 6) was of the opinion that the numbers of rays in the leaves in the middle of the rachis 

 must be looked upon as the most important specific character. This character, however, is only of 

 mediocre value, being useful only in adult specimens. Thus Hickson placed P. lusitanicum Broch in 



