This species, founded on specimens from the Lower Coal Measures of Shore, Lancashire[345], may exceed 4 cm. in length and has a breadth of 2·5 cm. In general plan it agrees with _T. Parkinsoni_ but there are certain well-marked differences: the micropyle is much shorter; the thick sarcotesta, attaining a breadth of 6 mm. at the base of the micropyle, is characterised by the presence of six peripherally placed vascular bundles (fig. 426, D, _v_) in contrast to the deeply embedded bundles of _T. Parkinsoni_. Below the epidermis of the sarcotesta is a hypoderm formed of radially disposed plates of sclerous tissue similar to that of _Myeloxylon_ and different from the palisade-like hypoderm of the type-species. Within the sarcotesta is a hard shell, the sclerotesta, characterised by three prominent ribs extending from base to apex and three shorter ribs which reach from the chalaza to about a third of the length of the seed. The fact that the sarcotesta and sclerotesta pass gradually into one another is a point in favour of the view that the integument is a single structure. There appears to be good evidence of the restriction of an inner flesh to the micropylar region, whereas this tissue in _T. Parkinsoni_ was probably continuous over the whole inner face of the sclerotesta. The sarcotesta is lacunar in its outer part as in some other types of Palaeozoic seeds, a feature probably connected with floating efficiency. _Trigonocarpus shorensis_ occurs in association with _Myeloxylon_ petioles, and there is a resemblance between the seed and the vegetative organs in the structure of the hypoderm as also in the structure of the secretory sacs which are particularly numerous in this species. Salisbury draws attention to the close resemblance between the form of _T. shorensis_ and the seeds found in organic connexion with pinnae of _Neuropteris obliqua_[346]. The species _T. corrugatus_ described by Renault[347] bears a close resemblance to _T. shorensis_. +Other Genera founded in part on Reproductive Organs which may belong to the Medulloseae.+ =Codonotheca=, =Schützia=, =Whittleseya=, =Dolerophyllum=, =Ottokaria=, =Strobilites=. =CODONOTHECA.= Sellards.