M2 W.j\LBale: 



Plumularia scabra Lamarck. (Plate XVII., Figs. 4-5). 



riuinukirla scabra, Lamarck, An. s. Vert., 1816, p. 127. 



Blainville, Man. d'Act., 1834-7, p. 478. Bale, Cat. 



Aust Hydr. Zooph., 1884, p. 145. Billard, Ann. Sci. 



Nat. (9), v., 1907, p. 322. Idem, Ann. Sci. Nat. (9), 



xi., 1910, p. 36. Idem, Siboga-Exp. i.. Plum., 1913, 



p. 47. 

 Plumularia effusa, Busk, Voy. of llattlesn., i., 1852, p. 



400. Kirchenpauer, Abh. Nat. Ver. Hamb., vi, 1876, 



p. 46, pis. i., v., figs. 4, 4b. Bale, Cat. Aust. Hyd. 



Zooph., 1884, p 129, pi. xviii,, fig. 5. Idem, Trans. 



and Proc. Roy, Soc. Vict., xxiii., 1887, p. 94. 

 Acanthella effusa, AUman, Kept. Chall. Plunx., 1883, p, 27, 



pi. vi., figs. 1-4. Marktanner-Turneretsclier, Ann. 



k.k. naturh. Hofmuseums, v., 1890, p. 260. Kirkpat, 



rick, Sci. Proc. Roy. Dublin Soc, vi. (N.S.), 1890, p. 



610, pi. xiv., fig. 4. Campenhausen, Abh. d. Senckenb. 



naturf. Gesellsch. Frankfurt-a-M., xxiii., 1897, p. 315. 

 I have been favoured by Dr. Kirkpatrick with fragments of both 

 Busk's and Allman's specimens of this species, uliich I had not 

 previously seen. It is very closely allied to F. hadl'i Kirchenpauer 

 {P. Eamsayi Bale), and some of the points of contrast between 

 them to which I referred in the '' Catalogue " do not exist, but 

 were due to errors in Kirchenpauer's figures and description. The 

 hydrocladia in P. scabra are borne on stout bracket-like apophyses 

 exactly as in P. badia, but in all the specimens which I have seen 

 they spring more from the front of the hydrocaulus (a feature 

 also noted by Kirchenpauer). The two species are so much alike 

 that small specimens cannot be differentiated by the naked eye, 

 but they differ noticeably in the form of the liydrothecae, and the 

 position of the anterior saicothecae, as well as in the spinous 

 processes which distinguish P. scahra. 



One of Kirclienpauer's figures — PI. v., fig. 4b. — is good, only 

 erring in showing a septal ridge on the proximal side of the 

 anterior, sarcotheca, instead of between it and the hydrotheca. As 

 AUman has already noted, the stout spines which towards the tips 

 of the branches replace the hydrocladia, are not, like the latter, 

 jointed to the bracket-like apophyses, but are continuous with 

 them. Between these and' tlie ordinary hydrocladia, however, 

 transition forms are found, which, commencing as hydrocladia, 

 terminate in the characteristic spines. 



