84 MR JAMES RITCHIE: SUPPLEMENTARY REPORT ON 



perisarc. The contents of the gonangia were frequently missing, and in no case were 

 they in a state fit for minute examination. 



Measurements : — 



Internodes, length 

 „ breadth 



Hydrotheca, portion free 

 „ ,, fixed 



,, diameter at mouth 



Gonangium, length 



maximum breadth 



O-Sl-0-94 mm. 

 0-10-0-12 „ 

 018-0-20 „ 

 0'27-0-28 „ 



0-74 mm. 

 0-60-0-63 „ 

 0-45-0-53 „ 



In general build, in possessing chitinous proj ections from the base of the hydrotheca, 

 and in the structure of its gonangium, this species bears close resemblance to S. cornicina 

 (M'Crady) as described by Nutting. The latter species, however, is to be distin- 

 guished by the tubular shape of its hydrothecse, by the nunaber of the marginal teeth 

 and of the opercular flaps, by the narrowly oval outline of its gonangium, and by the 

 fact that the gonangia are borne on hydrorhizal tubes at the base of the colony, and not 

 on the stem. 



Locality. — Growing on a Plumularian, Halicornaria longicauda, and on seaweed 

 (Codium, sp.), both from Station 81, Abrohlos Bank, Brazil. Lat. 18° 14' S.,long. 37° 

 58' W. Depth, 40-50 fathoms. Bottom deposit, coral. 20th December 1902. 



Previously recorded only from the Gulf of Mexico : Allman, 1877 ; Versluys, 1899 

 (Dry Tortugas) ; Nutting, 1904, lat. 29° 28' N., long. 87° 56' W. 



Thuiaria articulata (Pallas, 1766), ( = T. j^ectinata, Allman, 1888). 



In the earlier report, a colony of this species was recorded under Allman's name of 

 T. pectinata. The occurrence of an additional colony with gonangia reopened the ques- 

 tion of nomenclature, and an examination of Allman's type was made (through the kind- 

 ness of Mr R. KiRKPATRicK, of the British Museum). The examination assures me of 

 the identity of T. pectinata, Allman, with T. articulata, Pallas. 



The larger of our two colonies was some 6 cm. high, the height of Allman's speci- 

 mens being also " between two and three inches." The colonies are simply pinnate, with 

 a monosiphonic stem about 1 mm. in diameter at the base. The stem is partitioned into 

 regular and well-marked internodes, each bearing three pairs of opposite hydrothecse, 

 and from between the proximal and median pairs arises a pair of opposite pinnae. 

 Proximal to the first pinna-bearing internode a few destitute of offshoots occur, and on 

 these the number of hydrotheciB is not constant. Apart from these only one internode 

 has been observed in which three pairs of hydrothecse have not occurred ; and it is 

 clearly abnormal, for it lacks pinnse, has but one pair of hydrothecse, and is so short 

 that the hydrothecse project beyond it, free for nearly half their height. The pinnse 

 stand out from the stem at a wide angle, and they too are divided into distinct but 

 less regular internodes, each bearing from two to five pairs of sub-opposite hydrothecse. 



