THE BRACHIOPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 153 



p. 43)* of specimens of L. urn from 1 11 fathoms, East Cape Byron, Australia, may be 

 founded on a similar error in determination. 



Liothyrina xva (Brod.),var. notorcadensis, nov.t (PI. I. figs 1-3.) 



Hal>. Station 325 ; lat. 60 43' 42" S., long. 44 38' 33" W. (Scotia Bay, South 

 Orkneys). 6 fathoms. February 1, 1904. Sea bottom, sand. Temperature 32'5 F. 



06s. At this station some remarkably large oval forms of a Liothyrina were 

 obtained in very shallow water. These, for reasons given below, and in order to call 

 greater attention to them, I have ventured to describe under the above heading. 



Four specimens in all were obtained here, two large, one of medium size, and one 

 very young. 



The measurements of these examples are as follows : 



No. 1 (dead) . 



2 (live) . 



3 (dead) . 



4 (dead) . 



Examples Nos. 1, 2, and 3 are all very thick-shelled ; No. 4, being a juvenile, is 

 almost transparent. 



Example No. 2, which was attached by means of its peduncle to the larger specimen 

 (No. 1), is almost covered on its exterior with small coiled Serpulfe and Polyzoa. The 

 marginal portion exhibits curious radiating descending grooves. 



The largest specimen is very similar in general appearance to those obtained by 

 the French Antarctic Expedition, figured by OEHLERT (op. cit., pi. i.). The shell is 

 remarkably robust, and, judging from the crowding together of the growth-lines at the 

 margins, it is evidently a very old (gerontic) individual (PI. I. fig. 1 ). 



The interior of the dorsal valve exhibits a very distinct median septum extending 

 a third the length of the valve, as well as strongly marked muscular impressions. 

 The brachial support is, unfortunately, somewhat broken (see PI. I. fig. 3), but sufficient 

 remains for comparisons to be made with other forms. 



Outwardly this example presents the appearance of having been bored by an agency 

 similar to Cliona or one of the perforating Polyzoa, as the surface of the shell is covered 

 with branching vermiform groovings, some of which penetrate to the interior. 



The living example (No. 2), which was attached to the above, has provided material 

 for the study of the general characters of the spiculfe, etc., and 1 am much indebted 

 to Dr F. BLOCHMANN, to whom I submitted this and other examples, for his kindness 

 in comparing these with the specimens obtained by the Swedish Expedition at South 

 Georgia. 



* Not referred to by BLOCHMANN (1912). 

 t From the locality. 



(ROY. soc. EDIN. TRANS., VOL. XLVIII., :(7"> ) 



