480 MISS G. L. ELIE8 ON THE GEAPTOLITE [Aug. 1 898, 



shows one of the 5th order, but in the other specimen there appears 

 to be no stipe of a higher order than 4. The stipes of the 1st 

 order divide dichotomously, but all subsequent branching appears to 

 be latei'al ; the lateral stipes are always on the same side of the 

 main stipe, and curve in the same direction. The branching takes 

 place at very irregular intervals, but there appears to be sometimes 

 a general plan that the distances between the stipes are greater 

 the more remote the stipe is from the base. Thus in one specimen 

 lateral branching traced along the main stipe takes place (a) after 

 1 inch (25-4 mm.), (6) after 1^ inch (31-7 mm.), (c) after 1| inch 

 (38 mm.). The angles between the stipes gradually decrease : — 



(a) Angle between two stipes of Order 2 = 90° 



(b) „ „ of Order 3 = 75° 



(c) „ „ of Order 4=65° 



There are twenty-five thecae in the space of an inch (ten in 10 mm.). 

 Both specimens in the Keswick Museum show a small square disc 

 whose diameter is about ^ inch (6*3 mm.) ; but the type-specimen 

 has none, nor has the specimen in the Woodwardian Museum. 



Occurrence. — Middle Skiddaw Slates. 



Localities. — Scale Hill; Low Bridge, Whit Beck, near High 

 Lorton ; Grisedale Pike. 



Genus SchizoyraptuSj Nich. 



SCHIZOGEAPTTJS EETTCULATTJS, Nich. 



1868. Dichograpsus reticulatus, Nich. Quart, Journ. Geol. Soc. vol. xxiv, p. 143, 

 pi. V, figs. 4 & 5. 



1876. Schizograjptus reticulatus, Nich. Geol. Mag. dec. 2, vol. iii, p. 248. 



The stipes in this species are characteristically straight and rigid, 

 and the whole rhabdosoma resembles a branched Tetragraptus of the 

 quadrihracJiiatus-type. There are branches of three orders only. 

 The two stipes of the Ist order are very short, and measure together 

 not more than -f'j inch (2*1 mm.) ; four stipes of the 2nd order arise 

 from these as a result of dichotomous division. These constitute 

 the main stipes of the rhabdosoma, and from these are given off 

 lateral stipes nearly at right angles and all on the same side. The 

 first stipe of the 3rd order is given off at a distance of about | inch 

 (6"3 mm.) from the point of dichotomy, and the second at a distance 

 of -^2 inch (10*5 mm.) from the first. On one main stipe whose total 

 length is 3 inches (76 mm.) only two lateral stipes are visible, and 

 both these arise within the first |- inch of its length (17 mm.). On 

 no stipe have I seen more than two stipes of the 3rd order; there- 

 fore it would seem likely that none were developed. 



The thecse number twenty-five to the inch (ten in the space of 

 10 mm.), and are inclined at a low angle. 



Localities. — Scale Hill, near Crummock; Barf. 



SCHIZOGEAPTTJS TAEDIETJECATTJS, Sp. UOV. (Fig. 7, p. 481.) 



This species is very closely allied to the foregoing. It also 

 strongly recalls a Tetragraptus of the quadribrachiatus-type. 



The rhabdosoma consists of two short branches of the 1st order 



