98 G. F. MATTHEW ON THE 



occur in the collection from St. John ; the size, relative position and inclination of the 

 hydrothecœ, together with the general characters of the species, pointing all in that direc- 

 tion. One of the Levis, Qne., specimens of L. Logani now on exhibition in the cases of the 

 museum at Ottawa exhibits twenly-tivo hydrothecte in a space of twenty-one millimetres, 

 whilst one of the St. John specimens shows twenty hydrothecse in the same space. Some 

 of the leading characters and features of the genus and species, as seen in well preserved 

 specimens however, are absent in the specimens examined from St. John. Some of the 

 stipes are exceedingly like those of Clonograptus." 



TETRAGEAPTUS, Salter. 



TeTRACiRAPTUS QUADRIBRACHIATUS, Hall. 

 Graptolithus qiiadnbrachialun, Hall, Can. Org. Bern. Dec. ii., p. 91. PI. v. ix, vi. 



This species occurs in the graptolite shales at the Suspension Bridge (Div. M), but is 

 not plentiful. 



Dr. Ami's note is as follows: "The single representative of this species in the col- 

 lection from St. John is verj^ fairly preserved and has ten hydrothecœ in the space of ten 

 millimetres, whilst one of the type specimens from Point Levis (vide " Grraptolites of the 

 Quebec group, Dec. ii., PI. 5, fig. 2, by Hall) shows eleven hydrothecœ in the space of ten 

 millimetres. This species is characteristic of a low zone of graptolites at Point 

 Levis, Que." 



DIDYMOGEAPTUS, McCoy. 



DiDYMOGRAPTUS PATULUS, Hall. 

 Graptolithus pahdvs. Hall, Can. Org. Rem. Dec. ii., p. 71, PI. i. 



This species occurs with the succeeding and is nearly as common. A variety occurs, 

 or a different species, in which the branches are ascending, as represented for D. hirundo, 

 Salt., in Memoirs Geol. Surv. Grt. Britain, vol. III., but they ascend at an acuter angle. 



Dr. Ami's note on the specimens sent to him is as follows : " There are six speci- 

 mens bearing this designation, marked by me as follows n, ft, y, S, e, Ç. 



" a. This form is the same as 'A ' of No. 6 under D. nilidns, Hall, [see further on, G-. 

 F. M.] and along with ft, S, t and Ç may be D. patulus, Hall, whilst ô and « are evidently 

 co-specific with the form No. 8 called D. Mi undo ?, Salt., which may also be D. patulus, 

 Hall. In fact I should feel inclined to refer these to this species of Hall rather than to the 

 other. Y is the same as '»', whilst ft is like a crushed form of a Tetragraptus like T. serra = 

 T. bryonoides. Hall, ( = T. cudiiceus, Salt.), Tetragraptm serra is Brongniart's species, and 

 from Prof Chas. Lapworth's writings the two names T. serra and T. bryonoides are synony- 

 mous, whilst the former has the priority, yet Prof Lapworth always seems inclined to 

 keep up Hall's very appropriate term and designation T. bryonoides. 



" y is probably a Didymograptus cf D. patuhs, Hall." 



DiDYMOGRAPTUS NITIDUS, Hall, var. 

 Graptolithus iiilid^tf, Hall, Can. Org. Rem. Dec. ii., p. 60, PI. i. 

 A species with rather narrow stipes, which appears to agree with this is somewhat 



