J. W. Jackson — The Brachiopod Liothyrella. 75 



Tasmaniaii waters, show that it is now to be I'elegated to the second 

 group, as this species has no cirri bases.' I had independently 

 arrived at a similar conclusion from the construction of its loop and 

 hinge-processes, details of which are given on a later page. 



Of the first group I have only been able to study actual specimens 

 of Zi. uoa and its var., and L. antarctica, as well as some recent and 

 fossil specimens of L. ajjinis — the recent from off the Algerian coast, 

 the fossil from the Pliocene of South Italy and Sicily. 



Z. uva and L. antarctica have extremely fine radiating strise on the 

 surface of the shells, and both possess a slight mesial dorsal septum ; 

 this is at times somewhat more noticeable than in L. vitrea and 

 L. eubensis, though not to any great degree. L. uva, var. notorca- 

 densis, and L. blochmanni show similar features (see Jackson, op. 

 cit., 1912). 



On Z. affinis from Algeria the radii are clearly present and 

 wide apart; there is also a fine mesial septum in the umbonal 

 cavity of the dorsal valve ; the shells are rounded in outline. Of the 

 fossil examples, two forms are present — elongate-oval (atypical 

 afftnis) and rounded (cf. arctica) — from the two localities, viz. Calabria, 

 S. Italy, and Messina, Sicily. These two forms are too near each 

 other to warrant separate distinction. The radial striae on both forms 

 are very indistinct, but they can sometimes be made clearer by 

 slightly moistening the surface of the valves. In type of cardinalia 

 they agree with the Algerian Z. affinis, but the presence of a mesial 

 septum is a little uncertain. 



The presence or absence of radial striation on Terebratulids should 

 form an interesting study. The following are a few of the occurrences 

 which have come under my notice. Of Jurassic Terehratulce, 

 T. phillipsi, from the Inferior Oolite of Broadwindsor, has incipient 

 radii, especially on the anterior portions of the valves. On T. inter- 

 media, from the Cornbrash of Kidlington, the radii are likewise 

 present on the anterior and lateral portions of the shell. Among 

 Cretaceous forms, radial striation is fairly strong and wavy all over 

 the shell in T. sella from the Lower Greensand of Hythe and 

 Wellingborough. T. depressa, var. cyrta, from the Lower Greensand 

 of TJpware, also shows striae radiating from the beak : the dorsal 

 valve of this form has a mesial septum. On several of the Chalk 

 species presumed to belong to Liothyrina, e.g. T. carnea, T. semi- 

 glohosa, etc., the striae can also be detected. They are fairly wide 

 apart and appear to be just below the outer layer of the test: they 

 are very indistinct and can only be seen on holding the shell in 

 a particular position. My observations have been made on T. carnea 

 from Gravesend, Norwich, Caburn, and Maestricht, and on T. setni- 

 globosa from Lewes and other localities. T. c«rw<?« possesses a distinct 

 mesial dorsal septum. A specimen of T. ohesa, from "Chalk, 

 Sussex (?)" , in my collection, is also radially ribbed, especially on 

 the flanks. The radii extend from near the beak to the anterior 

 border, and are closer together and more distinct than in 2\ carnea, 



■ Blochmann, '' Some Australian Brachiopods" : Papers and Proc. Eoy. See. 

 Tasm. for 1913 (1914), pp. 112, etc. 



