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IIAEDIVICA'E'S SCIENCE-GOSSIP. 



Macrotrachela papulosa. 



As long ago as July 1S89, amongst the beautiful 

 feather moss, T/iuidium tamariscinum, growing in a 

 thicket at Hindover, in Sussex, I met with a Callidina 

 which presented the peculiarity of being covered, 

 about its foot, wilh conspicuous blunt papillae. But a 

 solitary individual was seen, and a rough sketch and 

 a few notes were all that could be secured of the 

 unfamiliar form. I never came across a second 

 specimen until in September last, when examples of 

 what is evidently the same creature occurred to .me 

 from similar moss taken from old tree-stumps in 

 Epping Forest, near Chingford ; and I have since 

 seen numerous other specimens from near Epping, 

 again amongst Thuidiicm, and also from Wanstead 

 Park. These more recent examples I now proceed 

 to describe. 



The most obvious characteristic of this form, next 

 to the possession of the tubercles already referred to, 

 is that the greater portion of the integument is very 

 beautifully marked wilh fine raised dots, giving a 

 shagreened appearance to the skin. This dotting is 

 most evident upon the dorsal surface, but occurs also 

 upon the ventral face both of the trunk and the neck- 

 base, only those portions of the foreparts and foot 

 being destitute of the shagreening which are not 

 exposed during complete retraction of the creature. 

 Even the tubercles themselves are covered with dots. 



The general disposition of the papilla; follows that 

 of the spinous processes of the last described species. 

 Indeed, so similar in this respect, as well as in the 

 broad, flattened outline of the body, and the pro- 

 portions of the corona, are the two species, that I 

 have hesitated between regarding them as distinct 

 forms, or as merely extreme varieties of one species. 

 But, in addition to the fact that I have not found the 

 two intermingled in one gathering, the constant 

 differences in the form of the foot-spurs, and the 

 number of teeth upon the rami, and the presence of 

 the peculiar skin-marking in the present form (which 

 is never seen in multispinosa), make it clear that we 

 have to deal with distinctly separate species. 



The integument is, in M. papulosa, evidently of 

 considerable firmness of texture, since it resists 

 decomposition long after the removal of the soft 

 internal tissues. I have seen empty skins, with their 

 tubercles and dotting complete ; the stiffened in- 

 tegument thus approaching in character the fully 

 chitinized lorica of Dinocharis. 



Upon the neck, at the level of the dorsal antenna, 

 and close behind the position of the infolded coronal 

 lobes, occurs a blunt angular projection upon each side, 

 wilh a half-circlet of small rounded papilla; ventrally. 

 The succeeding, basal neck-segment bears two con- 

 spicuous, down-curved, blunt or acute, conical 

 lateral protuberances, having very wide bases. These 

 processes upon the neck project from and serve to 

 guard the anterior opening of the body in complete 



retraction of the animal. The thick basal neck-joint, 

 though itself fully of as stout consistence as the tiunk 

 and similarly shagreened, has its anterior border of 

 membranous texture, and this frilled edge covers in 

 and protects the more frontal parts during retraction. 



The bold lateral skin-corrugations of the trunk 

 bear several usually prominent blunt projections 

 corresponding to the bristle-like appendages of M. 

 multispinosa. The dorsal longitudinal folds of the 

 integument are indistinct in retraction, but usually 

 very conspicuous when the creature crawls. The 

 rearmost segment of the trunk, just above the cloacal 

 orifice, bears a dorsal row of five conspicuous 

 tubercles arranged transversely ; these vary in differ- 

 ent individuals from mere hemispherical knobs to 

 quite elongated digitiform processes, but are always- 

 prominent objects, since they form the apparent 

 termination of the body as the creature lies with foot 

 retracted within the trunk. In some specimens, if 

 not in all, an extra papilla, smaller and less notice- 

 able, occurs upon each side of the obvious five. 

 Immediately in front of this cross row, the same 

 hindmost trunk-segment bears a pair of tubercles, 

 closely approximated side by side upon the median 

 dorsal line, and further forward, a single median 

 pimple ; all these are plainly shagreened, like the 

 general surface of the body. No ventral papilla; 

 exist upon either trunk or foot. 



The very short foot, of four joints, carries two 

 cross-rows of small tubercles dorsally, six papilla; to 

 each row, those of the hinder row very irregular and 

 truncated projections. The third foot-joint bears the. 

 usual spurs, which are very small, blunt, obliquely 

 apiculated processes, with no interspace ; in shape 

 they somewhat resemble those of AT. guadricomi/era.. 

 The foot ends in three very short, thick, truncate,, 

 fleshy toes. 



The expanded corona is identical with that of 

 multispinosa, of two distinct lobes, with a deep 

 median sulcus equal in width to half each wheel ; the 

 whole being a little wider than the neck, and just 

 half the greatest widlh of the trunk. 



The frontal column is fairly long and stout, ter- 

 minated by the usual decurved membranous hood, 

 appealing hook-like in side aspect, beneath which are 

 strong active cilia, forming the anterior disk foe 

 attachment of the animal when crawling. 



The dorsal antenna is long, equalling in length the 

 column, and very nearly or quite equal to the neck- 

 width ; it is two-jointed, constricted below its- 

 summit, and bears thereon three diverging tufts of but 

 slightly radiating long seta;. 



The mastax is rond-ovate, and each ramus is. 

 crossed by three prominent teeth, with a fainter 

 fourth. The salivary gland apparently unilobed, 

 and very granular in one specimen. 



Food in stomach not moulded into pellets. Paired, 

 gonads and moderate contractile vesicle normal. 

 Lateral canals not detected. 



